1. Field of the Invention
The present invention relates to a water cooling device of a vertical multi-cylinder engine.
2. Description of Prior Art
A conventional example of the water cooling device of the vertical multi-cylinder engine has a cylinder block one side wall of which is provided with a side water passage extending along a longitudinal direction of the cylinder block, like the present invention. The cylinder block has an interior space provided with a cylinder jacket, into which cooling water from a radiator is introduced through the side water passage.
Conventionally, the engine of this type has an outlet of the side water passage opposed to an upper portion of the cylinder jacket.
The conventional technique has the following problems.    (Problem) Each cylinder wall has an upper and a lower portions warmed and cooled ununiformly.
The side water passage has its outlet opposed to an upper portion of the cylinder jacket. A large amount of cooling water which has flowed out of the outlet of the side water passage enters into the upper portion of the cylinder jacket without passing a lower portion of the cylinder jacket. And the cooling water dwells at the lower portion of the cylinder jacket to result in ununiformly warming or cooling the upper and lower portions of each cylinder wall. Thus, in warm operation, each cylinder wall has its lower side portion hardly warmed to result in a likelihood of seizing a piston. Further, in normal operation, each cylinder wall has a lower side portion insufficiently cooled. This results in producing a gap between the lower side portion and a piston ring to easily cause a blow-by gas leakage and an oil rise-up into a combustion chamber.